I would go with Def-Tech as well and avoid their internal sub models as this can produce some issues - especially if a sub goes out you have to send the whole speaker in for repair.
C/L/R 2000 - yes, very good center, but for stereo, perhaps BP-20s or BP-30s which you can find on eBay and Audiogon for excellent pricing at times.
Surrounds/Rears? BPX models are good choices.
For a sub, I would simply pick the best one that meets the needs of the room and fits the budget. IMO you can't have to much of a sub, but you can have a very poor sub. Always get quality over quantity. Velodyne HGS is awesome, digital drive is better. There are tons of recommended subs all over this site.
Granted - I'm just recommending you my system
Axiom has some nice complete theater packages which should just be considered fairly incredible for your enjoyment...
http://www.axiomaudio.com/epic80_600main.html#